Isolation, Biological Activity And Secondary Metabolite Investigations Of Fungi From Special Habitat

Natural products are important source of the drug discovery, microbial secondary metabolites is one of the significant components of natural products. Microorganisms derive from special eco-environment have formed a series of physiological adaptation mechanisms, they provide the potential of producing novel metabolites.In this thesis, isolation of mangrove fungi were achieved by rose bengal medium and PDA, LCA with carbendazim, thiophanate-methyl or procymidone.116strains were isolated. PDA with procymidone is the most effective for the isolation of mangrove fungi.Rose bengal medium, PDA and Medium A were used for antarctic fungi isolation at14℃and28℃,142strains were isolated. Most of the antarctic fungi were isolated by14℃, only7strains were isolated by28℃.178strains were fermentated on GPY and PDA solid medium (or in GPY and PDA liquid broth). Six bacterial and two fungi were used as indicator strains in the antimicrobial activities assay.114strains (64.8%) showed activities against at least one kind of indicator microorganisms. MTT method was used in the tumor cytotoxic activities assay, At the concentration of50μg/mL,82strains (46.1%) showed activities against at least one kind of indicator cell line.38strains of mangrove fungi and37strains of antarctic fungi were selected to ITS gene sequence analysis. The experimental results showed that38mangrove fungi were classified into20genera,37antarctic fungi were classified into7genera. The mangrove fungi and antarctic fungi didn’t share a genera except for Penicillium sp..One strain of mangrove fungi and antarctic fungi were selected to secondary metabolites research respectively, five compounds were isolated while one of them is new.Three compounds were isolated from strain N14-21(Pseudeurotium sp.), including pseurotin A (N14-21-1), Indole-3-lactic acid methyl ester (N14-21-3) and Indole-3-lactic acid (N14-21-4). Two chlorinated diphenyl ethers were isolated from strain0221-39(Phoma sp.), LLX-1has not been reported before.Five compounds’ biological activities were tested. LLX-1and LLX-3showed antibacterial activities versus S.a, B.s, B.p and A.n. N14-21-3, N14-21-4, LLX-1and LLX-3showed weak antioxidant activities.This thesis show that tremendous fungi are contained in special eco-environment such as mangrove and the antarctic continent. Large numbers of them display antimicrobial and tumor cytotoxic activities, which are able to yield novel secondary metabolites. These investigations made them the crucial source in the study of natural products.